Mechanical walking animal



July 18, 1961 1 A. M, BENNETT 2,992,831

MECHANICAL WALKING ANIMAL Filed Dec. 3. 1959 IN VEN TOR.

AVERILL M. BENNETT ATTORNEY.

United States Patent 2,992,831 NIECHANICA'L WALKING ANIMAL Averill M. liennett, 6709 Irvine Ave., Los Angeles, Calif. Filed Dec. 3, 1959, Ser. No. 857,226 2 Claims. (Cl. 2801.17-7) This invention relates to a mechanical walking animal and, more particularly, to an improved construction for such an animal to permit greater facility of operation over that shown and described in United States Letters Patent Number 2,226,893, entitled Mechanical Walking Animal, issued December 31, 1940 to the present inventor.

One of the problems encountered in the operation of the device shown and described in the aforesaid patent is the difliculty in obtaining forward movement. Such difiiculty is due to the basically stable configuration of the legs and feet in their disposition relative to their axes of pivotal oscillation. That is, each foot being arcuately curved on a radius about the axis of its pivotal rotation or oscillation, each foot acts as though it is a portion of a perfectly circular wheel which, of course, provides inherently no more likelihood of forward motion than rearward motion. Hence, in operation, a simple side-to-side rocking motion imparted to the device fails to provide either forward or backward movement of the device since each foot and leg simply finds its own naturally balanced position depending from and with respect to its pivotal axis, and the placement of the body weight on one side or the other does not cause the device to roll upon the feet. In the absence of an independent force directed in either the forward or backward direction, as is necessary in pulling or pushing any wheeled vehicle, the device does not have any tendency to move in either direction but remains stably positioned upon its wheel-like arcuate foot portions. In order to obtain forward movement, the operator, whether riding or manually manipulating the device, must exert a forward force upon the body of the device so as to roll the device upon its wheel-like foot portions and, thereby, cause an unbalancing of the natural gravitational disposition of the legs and feet about their respective pivotal mountings so that, upon subsequent rocking so as to let such legs and feet hang freely, they will swing forwardly in the direction of such natural gravitational dependence. In the case of an operator who is riding the device, such operation requires skilled coordination of sideward rocking and forward lurching which often results in toppling the rider or the device. Similar problems of control are presented to the manual operator as well.

According to the present invention, there is provided a mechanical animal, adapted for walking movement upon a surface by being rocked from side to side, comprising a body supported upon a plurality of transversely spaced legs, each leg being mounted for pivotal oscillation about a transverse axis and having a foot portion, each foot portion comprising effectively heel and toe portions. The location of the center of gravity of the combined leg and foot portions is such with respect to the pivotal axis that, when freely hanging therefrom, the combined leg and foot portion will hang with the heel portion closest to the walked upon surface, i.e., the heel portion will contact the surface when the body is rested upon that leg. The leg and foot are so configurated that, when the body weight is rested upon the leg with the heel portion in contact with the surface, torque is developed in a sense such as to cause forward movement of the body upon the leg. Such movement causes the leg to rock upon the foot and, consequently, the foot to rock from its heel-contact position to a toe-contact position. Upon sidewise rocking of the body to rest upon the other feet ice so as to remove the toe-contacting feet from contact with the surface, such feet and their legs will hang freely and swing forwardly to place the heels in position for contacting the surface again. Thus, rocking the body in only a sidewise manner will cause alternate heel-andtoe contact and movement of the device in a manner simulating a natural walk.

Therefore, it is one of the objects of the present invention to provide an improved leg and foot construction for a walking animal whereby forward movement of the animal can be obtained by a simple side-to-side rocking motion.

Another object of the present invention is the provision of a mechanical walking animal with legs and feet so balanced and configurated as to obtain heel-to-toe movement in response to the weight of the body alone.

A further object of this invention is to provide a mechanical walking animal which is selectively unbalanced in a forward direction and having legs and feet adapted to perform lieel-to-toe movement upon the occurrence of such unbalance.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, in which;

FIGURE 1 is a side elevational view of a mechanical walking animal in accordance with the present invention, showing the animal positioned upon all four feet and approaching a forward toe-contacting position;

FIGURE 2 is a rear elevational view with the animal rocked sidewardly upon its right feet;

FIGURE 3, is a side perspective view showing the animal rocked sidewardly onto its right feet, with its left legs and feet hanging freely;

FIGURE 4 is an exploded enlarged perspective view, showing a pair of legs and the pivotal mounting means therefor; and

FIGURE 5 is a diagrammatic view, illustrating one form of configuration of the foot and leg so as to obtain an unbalanced condition for the animal in a forward direction.

Referring to the drawings, there may be seen a toy animal having a body, indicated generally at 10, and a head 11, neck 12 and tail 13. Of course, natural animal appearances may be simulated and it will be understood that various sizes can be made for meeting this requirement and for other purposes, such as the construction of an animal large enough for a human rider and in such sizes and shapes as are indicated in US. Patent No. 2,226,893.

Although a quadruped is illustrated, bipeds may be simulated with some variations in construction to allow for stability in operation.

The body 10 is provided with front and rear left legs 14 and 15, respectively, and front and rear right legs 16 and 17, respectively. Referring to FIGURE 4 for a description of the mounting means for a pair of legs, such as front legs 14 and 16, there may be seen a mounting plate 18 adapted to be disposed against the underside 19 of the body 10 and having a hole 20 through which a screw (not shown) may be driven to secure the plate 18 to the body 10. The plate 18 is split so as to provide three tongues comprising a central tongue 21 and two lateral tongues 22 and 23, the latter tongue 23 being broken away in FIGURE 4 for convenience of illustration. The central tongue 21 is looped to provide a bearing sleeve for the axle 24. The axle 24 constitutes the axis for pivotal oscillation of the legs 14 and 16 which '24 from the toe and heel.

are apertured at 25 and 26, respectively, for disposition over the axle 24 and adjacent to the central tongue 21. A cotter pin 27 is then inserted through the hole 28 in the axle 24 and bent in the usual manner to maintain the leg 14 upon the axle 24; a similar cotter pin (not shown) is used on the other end of the axle 24 to similarly hold the leg 16. The function of the lateral tongues 22 and 23 will be discussed later in connection with the operation of the device.

Each leg, such as leg 1'6 in FIGURE 4, is provided with a foot portion 29 having a heel portion 30 and a toe portion 31. In the form illustrated, the foot portion 29 is provided with a continuously curved bottom surface 32 joining the heel portion 30 to the toe portion 31. A U-shaped frame 33 is secured to the lateral outside of the foot portion 29 at points 34 and 35 in the heel portion 30 and toe portion 31, respectively, above the level of the surface 32 so as to permit sideward rocking of the animal upon the foot portion 29, with the frame 33 acting as a limiter to prevent the animal from tipping over sideways, as seen in FIGURE 2.

Each leg and foot combination is shaped to have a center of gravity so located that, when such combination is hanging freely from the axle with its center of gravity in vertical alignment with the axle, the leg and foot are in a forward position as shown by left legs 14 and 15 in FIGURE 3. In such forward position, the heel portion 30 is the closest portion of the foot 29 with respect to a surface 36 upon which the animal is to walk. In the form illustrated, the leg is in a substantially inverted L-shape with the elbow portion 37 directed rearwardly from the axle 24. The foot portion 29 is preferably integral with the leg and disposed so as to form substantially an inverted T.

As seen in FIGURE 5, the effective concentration of weight at the center of gravity, which may be at the point indicated at 38, will cause the leg 16 to pivot about its axle 24 in a clockwise direction until the center of gravity '38 is disposed in vertical alignment beneath the center of the axle 24, and the heel portion 30 will be adjacent the surface 36; that is, the pivotal mounting 24 is substantially on a line through the heel 30 and the center of gravity 38 and above the latter to provide the desired turning moment on a freely suspended leg. Such pivotal rotation of the leg 16 and its foot portion 29 about their axis represented by the axle 24 is indicated in FIGURE by the solid line circle 39 which has its radial center at the center of the axle 24. Of course, the leg and foot do not rotate about a complete circle in operation of the device but simply oscillate through a relatively small arc of that circle 39. The bottom surface 32 of the foot portion 29 is preferably arcuately curved on a radius about a point rearwardly of the axle 24, such point being indicated, for example, at 40. For purposes of clarity in illustration, a dash line circle 41 has been constructed about the radial center 40 and includes the bottom surface 32 of the foot portion 29. As is more clearly shown in FIG. 5, the radius of the dashed-line circle 41 about its center 40; that is, the radius of curvature of the foot surface 32, is substantially equal to the distance from the center of the pivotal mounting 24 to substantially the middle of the surface B2 between the toe and heel of the foot. Hence, although the bottom surface 32 oscillation of such wheel portion is eccentrically displaced forwardly of the radial center 40 of such surface 32.

Thus, with the FIG. 5 construction, the toe 31 of the foot surface 32 inherently is nearer the center of the axle 24 than the heel 30 and the radius of curvature of the surface 32 about the center '40 is substantially onehalf the sum of the distances of the center of the axle When the bottom surface 32 is curved on a radius about a single point, such as point '40, the point of contact between such surface 32 and the walked upon surface 36 will be directly below such point 40, and the vertical force vector due to the weight of the body 10 upon the axle 24 will be forward of such point of contact. Therefore, upon application of the weight of the body 10 to the axle 24, as when the body 10 is rocked sideways thereupon as in FIGURES 2 and 3 or is resting evenly upon all four legs as in FIGURE 1, a forwardly unstable condition exists, which instability may be measured or defined in terms of the counterclockwise torque developed by the body weight acting downwardly through the axle 24 about the horizontal lever arm distance between the axle 24 and the point of contact of the surface 32 with the surface 36. Such torque causes the leg and foot to rotate in a counterclockwise direction about the axle 24. As a result, the bottom surface 32 of the foot portion 29 rolls from a heel-contacting position to a toe-contacting position, and the 'body 10 moves forward. This forward motion of the body 10 will continue until the elbow 37 of the leg abuts against the mounting plate 18 to halt rotation of the leg. Prevention of further rotation of the leg prevents any further forward movement of the body 10. The leg will then be in its rearward position with respect to the body. Upon sideward rocking movement of the body so as to rest upon the legs on the other side, the rearwardly positioned legs will be lifted out of contact with the surface 36 and permitted to swing freely, whereupon they will rotate in a clockwise direction and will assume the forward position as previously described.

Of course, it is preferred that all four legs and their feet be identical in construction in order to obtain uniformity in the walking gait, but variations between the legs and/or feet may be made to achieve any desired gait.

As a safety precaution to-prevent backward toppling of the body, the lateral tongues, such as tongues 22 and 23, of the mounting plate 18 are disposed in front of their respective legs so as to limit the extent of pivotal rotation in that direction, in a manner similar to the described limitation in the other direction caused by abutment of the elbow 37 against the mounting plate 18.

While, in the preferred embodiment, each bottom surface 32 is an arcuate curve about a single radial center, it should be understood that the bottom surface 32 may have other forms in accordance with the present invention, it being primarily necessary only that a torque be developed in the direction for causing forward move ment of the body. For example, rather than having a single radial center, the bottom surface 32 need not be circular but may be curved about many radii as long as such radii pass rearwardly of the axle 24 so that a forward-motion torque is developed.

While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. A mechanical animal adapted for walking movement by being rocked from side to side' comprising a body, a pair of front legs, a pair of rear legs, a foot on each leg, each foot having an outside convex surface terminating at opposite ends in a toe and a heel and being adapted to engage a supporting surface, and means pivotally mounting said legs on said body at a point substantially on a line through the heel and the center of gravity of the leg and above the latter for independent oscillation of all legs relative to one another about axes eccentrically forward of the centers of curvature of said foot curved surfaces and located a distance from substantially the middle of the surface between said toe to said heel substantially equal to the radius of curvature of said surface, such that the distance from the heel to the said axis thereof is greater than from the toe thereof to said axis, whereby free suspension of each said leg from said body causes said leg to pivot forwardly to place the heel of the foot of said freely suspended leg at substantially the lowest part of said respective foot.

2. A mechanical animal adapted for walking movement by being rocked from side to side comprising a body, means for supporting said body during normal usage consisting solely of legs comprising at least one pair of legs transversely spaced and means pivotally mounting said legs on said body for independent oscillation of said legs, a foot on each leg, each foot having a curved surface terminating at opposite ends in a toe and a heel and being adapted to engage a supporting surface, said curved surface of each foot having a center of curvature displaced slightly rearwardly of the center of said pivotal mounting of its respective leg and being formed on a radius substantially one-half the sum of the distances from the center of said pivotal mounting to said toe and heel thereof, and each of said legs having a center of gravity such that free suspension of each said leg from said body causes said leg to pivot forwardly to place the heel of the foot of said freely suspended leg at substantially the lowest part of said respective 10 foot.

References Cited in the file of this patent UNITED STATES PATENTS 

